Pre-operative preparation, often called prehabilitation or “prehab,” is a targeted physical preparation program designed to maximize a patient’s physical condition before orthopedic procedures like knee surgery. Engaging in a structured exercise routine and making lifestyle adjustments can significantly influence the body’s ability to tolerate surgical stress and accelerate recovery. Studies indicate that patients who participate in prehab often experience better post-operative outcomes, including improved strength and function. The goal is to build physical resilience, ensuring the body is in the best state to progress through post-surgical physical therapy.
Strengthening the Supporting Muscles
Muscle atrophy frequently occurs in the affected leg due to reduced activity and pain associated with the underlying knee condition, making pre-surgery muscle conditioning a primary focus. Maximizing the strength of the muscles surrounding the knee joint—specifically the quadriceps, hamstrings, and glutes—helps stabilize the joint and reduces the load on the joint immediately after the procedure. Stronger muscles pre-surgery serve as a reserve, mitigating the inevitable muscle loss that occurs during the initial post-operative recovery phase.
One foundational exercise is the Quad Set, or thigh squeeze, which focuses on activating the quadriceps muscle without moving the knee joint. To perform this, lie on your back with the leg straight and press the back of the knee down firmly, tightening the muscle on the top of the thigh. Holding this contraction for five to ten seconds and repeating it for 10 to 15 repetitions helps maintain nerve-muscle connection and strength.
Another low-impact movement is the Straight Leg Raise, which further builds the quadriceps and hip flexor muscles. While lying on your back with the non-surgical knee bent for support, tighten the thigh muscle of the surgical leg and slowly lift the entire leg off the ground, keeping the knee straight. Lift the leg only about 12 inches and hold the position before slowly lowering it.
To address the muscles that stabilize the hip and pelvis, Gluteal Sets and Clamshells are useful additions. Gluteal Sets involve squeezing the buttock muscles together and holding the contraction for five seconds. For the Clamshell exercise, lie on your side with knees bent, keep the feet together, and lift the top knee upward without letting the hips roll backward. These exercises strengthen the hip abductors and rotators that are important for walking stability post-surgery.
Improving Flexibility and Joint Mobility
Maintaining or improving the knee’s existing range of motion (ROM) is a goal of prehabilitation, as it directly correlates with post-operative success. Stiffness and contracture can develop quickly when a joint is painful, and achieving a good ROM before surgery sets a higher baseline for recovery. The ability to fully straighten the leg (extension) and bend it sufficiently (flexion) are prerequisites for a smoother recovery.
Gentle, controlled movements are used to lubricate the joint and prevent soft tissues from tightening. A simple exercise for knee flexion is the Heel Slide, where you lie on your back and slowly slide the heel toward the buttocks, bending the knee as much as is comfortable without sharp pain. This movement is performed slowly and typically repeated for 10 to 15 repetitions.
To improve extension, Seated Knee Extension stretches are often recommended. Sitting on a chair with the heel propped up on another surface allows gravity to assist in a gentle stretch. Holding this supported stretch for five to ten minutes helps elongate the tissues and improve the straightness of the knee.
Safety Guidelines and Pain Management
Any pre-operative exercise program must adhere to safety guidelines to avoid further injury or inflammation. It is necessary to consult with the surgeon or physical therapist before initiating any new physical activity to ensure the exercises are appropriate for the specific knee condition and surgical plan. A personalized prehab program must account for individual limitations and pain levels.
The guiding principle is to distinguish between acceptable muscle fatigue or mild discomfort and warning signs of joint irritation. Muscle burn or a dull ache that subsides quickly after stopping the exercise is acceptable. However, any sharp, shooting, or intense pain that increases during the exercise is a signal to immediately stop the activity.
Other warning signs include new or increased swelling around the knee joint or a feeling of instability or locking. The goal is to maximize function without exacerbating the injury, so exercises should be performed slowly, with control, and only within a pain-free range of motion. This prevents unnecessary inflammation, which could complicate recovery.
Maintaining Systemic Fitness
Maintaining overall systemic fitness is an important component of surgical preparation, beyond knee-specific work. A better cardiovascular and metabolic state improves the body’s resilience, positively influencing surgical risk and recovery speed. The focus is on low-impact cardiovascular activities that elevate the heart rate and maintain endurance without stressing the compromised knee joint.
Low-impact options are recommended:
- Swimming and water aerobics are highly recommended because water buoyancy minimizes the load on the knee while allowing for a full-body workout.
- Stationary cycling, particularly with a recumbent bike, is an excellent option, provided the knee can tolerate the required range of motion without pain.
- If lower body movement is too painful, an upper body ergometer allows for cardiovascular conditioning using only the arms.
Engaging in 20 to 30 minutes of these activities on most days helps maintain lung capacity and endurance, which aids in recovering mobility after the procedure. Additionally, maintaining a healthy body weight pre-surgery is advised, as it reduces the overall load on the knee joint and minimizes surgical risks.